Hydrological Response Of Slope Under Rainfall Infiltration Conditions

Landslide is a common natural disaster, its threat to life and property caused by more and more people's attention. Mechanism research occurred in Landslide has made a lot of fundamental results. Rainfall in particular Storm rainfall is an important factor in triggering landslides. Infiltration of rainwater during heavy rain increased soil saturation, sharp dropped in suction and caused a substantial decline in shear strength. Continuous heavy rain can cause groundwater level rise or occur transient groundwater flow over a relatively impermeable.Thus,when Continuous rainfall duration and intensity exceed a certain limit,it May cause instability or the resurrection of landslide. Slope in certain Geological setting and in a certain Mechanical Environment requires a certain rainfall, rainfall intensity or duration to promote slope damage. The monitoring of hydrological response and associated displacement of a slope under rainfall conditions is an important aspect of early warning of a landslide.In this paper, the Nanling Dalongshan 240m mountain slope lie in the south side of the Stone market in Shenzhen was used as a study site, and geotechnical instruments, including moisture probes, tensiometers, piezometers, in-place inclinometers and raingauge, were installed to measure matric suction, volumetric water content, pore water pressure, slope displacement, and rainfall. Based on monitoring data, the hydrological processes and slope deformation of the slope under rainfall conditions were then analyzed. It was found that when daily rainfall was relatively small, for example, on 18 April 2009 in the case of daily rainfall of 52.4mm/day,0.5m below the surface and lm depth of soil water content and matric suction responsed to rainfall respectively, whereas daily rainfall was relatively large, for example, on 23-24 May 2009, in two consecutive days daily rainfall exceed 100mm/day, matric suction and volumetric water content within 3 m responsed rapidly to rainfall infiltration, and groundwater level measured at P4 was very sensitive to rainfall, However, the pore water pressures measured at other piezometers did not vary significantly with rainfall. It was thus inferred that short-duration rainstorm can probably result in shallow failure. Meanwhile, cumulative displacement is relatively large within a depth of 3m of the slope, and cumulative displacement measured at inclinometer A is much larger than cumulative displacement measured at inclinometer B obviously. The trend of the cumulative displacement deformation of 5 Inclinometer is not increasing over time. For now the overall situation the cumulative displacement deformation is very small,the slope basically remained a steady state. Then utilizing indoor and outdoor experiments, For saturated-unsaturated soil conditions on site geological characteristics, using two-dimensional non-steady-state finite element program, establishing the mountain slope hydrology generalized model, simulated the transient flow field in the rainfall infiltration condition. By way of changes about Level of underground water and pore water pressure distribution in Seepage Analysis Studied the response to ground water of slope during different rainfall infiltration condition, The results also show that rainfall have greater impact on the shallow slope, It was thus inferred that short-duration rainstorm can probably result in shallow failure.